A real Ironworks Forum mod is still well off into the future. But I was able to achieve at least one thing. Altering the Skull item entry in CryptA.bol, by changing the 251 to 270, enabled me to place a Tome of Earth in the Crypt. 251 is the item number for Skull while 270 is the number for Tome of Earth.
This tome is the last one needed to become a Zenmaster, it is otherwise not found till near the end of the game.

Now we can see our way clear to solving some problems.
(1) Zenmaster ascension can happen much sooner, whenever convenient.
(a) Tome of Fire: near Hallway Maze in the Serpent Temple.
(b) Tome of Wind: You'll find it in a chest in the Boogre Hag's room.
(c) Tome of Water: in Collasium, near the library.
(d) Tome of Earth: In Cet's pyramid.
Tomes of Water and Earth can be placed in dungeons before Brimloch Roon?
Shurugeon Castle, Stout Mines and Dragon Spire are all possibilities. Dragonspire has an Oracle of Earth, that would be a good place for the Tome of Earth. Tome of Water can be placed anywhere there is water.

(2) Valkyrie ascension, I can try hacking the Warlock ascension in the Brimloch Roon Priest guild so that it grants the Valkyrie class not the Warlock. (If you want to do Warlock ascension in Brimloch Roon you can still do it at the League of Sorcery.)
A special Tome of the Valkyrie can be created, it can be required as one of the two ascension quest items. Shurugeon Castle is one place for it to be placed, the Castle is full of undead.

(3) Brimloch Roon Mage quests are given in the wrong order, Treant seeds can be left around some dungeon or other.
It might be possible to rewrite the relevant code in the GMData.pak, but that might take some time to figure out.

Edit:
Hacking the Brimloch Roon ascension for Warlock to produce a Valkyrie, this seemed to work as planned. There is currently no appropriate dialog for this approach. Existing dialog is based upon burning the lich's heart.
I turned a Whiskah Priest into a level 1 Valkyrie, complete with the Gravebind Trait.

Here, CopyGMDATA.PAK is the original file and GMDATA.PAK is the file after I hacked the Brimloch Roon Priest Guild. I retrieved the alterations I made to the GMData.pak with the File Compare function, found in the MS-Dos Prompt:

I can alter what items the guild wants for Valkyrie ascension. I have created a Valkyrie Tome in this regard, complete with a message telling the recipient to go to the Brimloch Roon Temple.
What I cannnot do is restrict ascension to women. Items can be created that are equippable by women only but I can't find a function in W&W that looks whether an item is equipped rather than just carried.

I have not checked that the Valkyrie actually attains the normal hit points, spells and skills when she gains levels. I believe she should, unless that is stored in the town record that I altered.
Edit:
I have just checked whether the Valkyrie seems to gain the usual spells and skills, as far as I could tell, she got all her usual spells and skills. Once the Valkyrie ascension is complete you may need to cancel the original Warlock training, the latter may still be running. Cancellation is quick and simple.
Only the Brimloch Roon Temple Warlock ascension is affected. If you are a member of the Priest Guild you can still do the Warlock ascension at the other two towns.

Monk ascension could be fixed too, about time. Maybe hack the Paladin ascension quest in one of the temples... Ishad N'ha comes to mind. You could hack the ascension there. As it is a hack of the Paladin ascension, you become a Monk immediately when you report back after praying at the Altar.

I don't know if the extra 44,0,0 is needed or not. What I can do is make the "No" choice in "Do you want to cancel your Monk training? Yes/No" link to the start of the Monk ascension code. This also means that I don't have to hack the Paladin ascension.

I rigged the Brimloch Roon Dojo ascension for the Monk class, when I said "No" to cancelling it enacted the class change. It only involved altering two bytes:
000054B0: F7 00
000054B1: 07 02
Now I need to do this for the Ishad N'ha Dojo too. By using the No answer rather than the Yes answer I have made it still possible for players to totally cancel if they want to.
I will try the ascension for a basic character not John Hubbard's level 50+ Zenmaster.
If the PC is a member of the Priest Guild but not a member of the Bushi Guild, she can arrange the ascension quest at the former and cancel it at the latter.

One other thing I need to research, can you be a Warlock and then use the hacked Warlock ascension to become a Valkyrie?